It seems I'm not the only one to have this problem. Someone asked about
it in the CDT group but got no reply...of course neither did my question
if he/she ever figured it out.

It does seem tied to only projects that are in SVN. It also appears
after a checkin or update or something. Sometimes it does disappear on
its own but it has always come back so far. This is rather new behavior
but I've updated nothing. Other members of the team may have and may be
working on the same projects...